Caster



FIG. 1 is a perspective view of a caster showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a left side elevation view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a rear elevation view thereof.

The broken line showing of a caster wheel and support plate is for illustrative purposes only and forms no part of the claimed design. 

I claim the ornamental design for a caster, as shown and described. 